all channels locked out

Hello all! I need some help. I'm trying to find my way around this radio, and to be honest, I believe I have managed to erase all the channels that a friend programmed in for me by trying to add a frequency as a channel manually. Anyway, I am no longer able to switch back and forth between...

A friend of mine gave me this radio, Radioshack PRO-95, still in the box. He then ran away giggling and mumbling "good luck". I now see why. My problem is no matter what I do it reads, ALL CHANNELS LOCKED OUT! I've read through the manual twice now and I've had at least five other people trying...